strange object seen over rural area twice in last month. viewed by many yet still unexplained. hoovering, darting, then vanishing.

traveling north on hi-way 52 west of decorah Iowa saw a bright object in the sky pulled over to side of road where others were viewing object object looked to be about 4 miles away hovered in a circular motion color changed from dull gray to shinny metalic continued hovering for @ 3 min. darted west than east then dissapeared not a cloud near it sun was to our backs called airport no flights at that time no craft that could fly in such a manner at airport. second time ive pulled over to the side of the road on my way home within the last 3 weeks, because there was people wathching something in the sky first time the object dissapeared behind a cloud this seemed alot less suspisious than just vanishing.